This is right on time, since I have 2 pairs of 206's that need a home.

The thing I really like is how Steve describes the sound as very big and open due to the venting out of the sides. That means that the change I've made to my tombstone horn idea should achieve a similar "big" sound with the horn mouth being around the entire perimeter of the cab.

[quote author=Chris K link=1153620804/0#3 date=1153688323]How'bout horn loading the six slots on the NFX!! NOW THAT WOULD BE AN INSANELY DIFFICULT BUILD!!!!!!!!!!!! [/quote]

Chris,That's kind of what I'm planning with the tombstone horn with the front view perimeter split up into 4 horn segments. This will give me a mouth area of almost half an Imperial but in a compact size cab. The build won't be too difficult, 3 large panels and a number of interior dividers all 3" wide. Sure there will be a number of odd angles, but the short 3" glueing length will permit imperfect but strong joints using one of the poly glues due to the strong support of the long dimensions having perfect joints.

I can't wait to see it John (the modded tombstone)! You're probably as much (maybe more) of an experimenter that Steve and Bob. You seem to have come up with some unique ideas. So I've absolutly avoided putting my SI coaxes in even a flat board and I've had them since last Nov. I think. What should I put em in? One of your designs?I wanna set of NFXs now. I'm shooting for a record breaking collection of Hi-Fi speakers in the houshold. Should be 6 0r 7 different pair by next year. Hows that sound? Pretty good I'd say. What are you listening to most these days?

I got my NFX plans and have been studying them. I think I will build a scale model first to check the fit of my cutting angles and dimensions. I have finally cleared out and reorganized my shop area so I am ready to go. It should be a fun build.

The plans are kind of tricky to find. There's a link at the bottom of Steve's design notes linked in his first post of the thread.

Before cutting wood, we need to get a clarification. As drawn, the A brace won't fit at the joints of the rear panel with rear left and and rear right panels. It looks like the A brace will need an additional 45 degree angle cut along the outer portion of its rear end.

I'll also make the adjustment to make the joint of the 3 rear panels a simple butt joint. The increased surface area of the angled joint should make it plenty strong without adding a complex joint.

Lastly, what exactly are "poly foam spheres"? Are we talking about rough surface or smooth surface styrofoam type balls available at hobby stores or are we talking about some type of foam rubber? If we're talking about polystyrene balls, which aren't very absorbent, then rounded chunks of foam rubber may be the first cab tweak.

[quote author=John in CR link=1153620804/15#15 date=1153877497]Before cutting wood, we need to get a clarification. As drawn, the A brace won't fit at the joints of the rear panel with rear left and and rear right panels. It looks like the A brace will need an additional 45 degree angle cut along the outer portion of its rear end.

Lastly, what exactly are "poly foam spheres"? Are we talking about rough surface or smooth surface styrofoam type balls available at hobby stores or are we talking about some type of foam rubber? If we're talking about polystyrene balls, which aren't very absorbent, then rounded chunks of foam rubber may be the first cab tweak. [/quote]

I interpret brace A as drawn in the callout, without a 45 degree angle at the rear, as correct. I think the 45 degree line you are viewing is the backside of braces B which are at different elevations than braces A. I see brace A as setting flat end grain (8 degree crosscut) against the back panel.

I see what you mean, but that leaves too little surface area for my tastes in the joint of the rear panel and P3's. I'd rather cut the 45 out of the end of the A brace or chisel out a space on the P3's for the A brace. Either way I will join the A brace to both the rear panel and the P3 on its side. Also, I don't care about the end grain of the rear panel being exposed, so I'll definitely make it wider and join with more surface area to the P3.

Lastly, I'm going to have to think about the 8 degree rake long and hard. I can see that it's going to be a real construction pain and more than likely, I'll just construct it square with some extra length at both ends of the full length panels. Then cut the rake angle off the top and bottom when I'm finished. The only possible detriment I see is that the B braces won't be perfectly horizontal or flush with the top and bottom. Maybe do only the B braces at the 8 degree angle? I don't see how anyone is possibly going to get a perfect fit on those P2 and P3 panels (you need an 8 degree angle on something at a 45 degree angle, so you have an odd shallow angle in 2 dimensions for those panels. I'd have to revisit the math involved to even figure out the angles, much less cut them).

[quote author=John in CR link=1153620804/15#19 date=1153950948] I don't see how anyone is possibly going to get a perfect fit on those P2 and P3 panels (you need an 8 degree angle on something at a 45 degree angle, so you have an odd shallow angle in 2 dimensions for those panels. I'd have to revisit the math involved to even figure out the angles, much less cut them). [/quote]

John,

The applied math here is using compound angle formulas. Imagine trying to build a four sided box that is narrower at the base than the top like a decorative flower pots. If you know the angle going up and how many sides you have, a compound angle formula will tell you the correct bevels and miters for cutting. I found the formulas browsing woodworking sites as many have fabrication tips and the compound angle question is a popular one. I will say that one must still be careful about when and how to apply the formulas.

As a check I went through the plans and sketched each piece in two dimensions. I then created a third view of the true angle of the bevels which also happens to be a view that is an end view showing the true width of the piece. I used basic trig to transfer the projections onto the 3rd view and the angles just jump out at you. I really need to buy some CAD software, but old habits die hard.

Well I completed a good part of my scale model. I made it full sized. I am quite pleased with the results as all the pieces fit together nicely. I used some scrap MDF from a home entertainment center I had been saving for a project. It was not too difficult to cut the bevels and miters after studying the plans. I checked my math with projection drawings so I was real sure the parts would fit. They did. This is not to say I cut the parts correctly each time. I want to emphasize here that the miscuts were the variety where I put the piece in the crosscut saw backwards or upside down from the correct way. Very easy to do if you get complacent. I initially cut the tricky ones much longer than needed and then cut them down to size after a first cut to check fit against the other part. I then could use the same saw setup for the opposite end. I cut the PL-xs from a four foot section and just worked it down from there. This method works well for getting a length of stock that has a good cross section from the long rips. The beginning and ending of a long rip sometimes lose constant cross section so if you cut a longer piece you will have a better chance of getting a good part to cross cut.

Also use the front as a template to set the length of the side pieces. Otherwise you will not have a flat top.

I would have finished the model but it was just too darn hot out there. I had to cut and assemble outside because of the MDF dust. That stuff is nasty. Tough on your saw blades too. I have had a mask on since yesterday in this heat. Yuck! All my tools are on rollers so I move them outside for cutting and welding. Did I mention already it is really hot outside.

My next step is to get some birch plywood to build a set to use. I will use the model pieces as a template for saw setups and as a guide to keep the cutting R/L pieces organized. Fun build. I have decided to go with real solid maple or cherry instead. btw, I will not use MDF again. My wife was not pleased with the dust. Wood chips she does not mind but MDF dust - NO!

Also when looking at the top of the plan, are the side ports open between P2-R on the right side and and the back verticle panel R and same as the left side P2-L and R?

No dimensions given for pedestal and top and bottom boards! will these be available later or do we just have to try and build it with the info we have?

Manowar ??? [/quote]

What piece are you referring to as the baffle?

The opening in the back is along braces B between p2 and p3.

The dimensions are all there. Look again.

However, the rear spikes are drawn in a different location in the front view than the plan view. Front view shows rear spikes outside the speaker width and the spikes are clearly inside the 4.3 inch square in the rear. No big deal it just illlustrates you can put them where you want.

[quote author=Manowar link=1154300940/30#30 date=1154298795]I still don't understand what the orange shaded area of the top view is supposed to show?

I understand the front and side view of the orange area...a base with three spikes!

Can someone clarify,

Thanks! [/quote]

You asked about a baffle before. It was not getting into my head that the baffle is the plate the speaker is attached too.

The orange part in the top view is the same part as the front and side views. The only visible part of the orange base in the top view are the semicircle Mickey mouse ears at the very back end of the bottom plate. Study the side view closely and you will see a vertical line on the orange base just to the left and down from the lowest brace B where it is labeled as "B". This vertical line is the front intersection line of the semicircle with the square portion of the bottom plate.

I also notice that the spikes are in a different position in each of the three views.

How about, instead, you just send me those "This is right on time, since I have 2 pairs of 206's that need a home. " ;D

[/quote]

RMT,

Once I invest in shipping and taxes to get drivers into Costa Rica, it makes no sense selling them to be shipped somewhere else. I like having four anyway for comparitive purposes as I begin to mod them and build enclosures.

[quote author=RFZ_Quest link=1154300940/30#37 date=1154396320]For some reason this third party source for uplinking photo's has been a problem for some. They show up with my server but when refresh is hit, they show red x'd blocks! Try right clicking on the mouse and click on show picture. I could always transfer these pictures from my web domain as that has never been a problem. If everyone is having this difficulty, let me know and I will transfer the uplink from my website.

BTW: I had several more pictures of these cabinets posted but they obviously were deleted by the eye in the sky. [/quote]

What kind of glue are you using with the prefinished MDF? Or do you just remove the finish at the joints? [/quote]

Thanks. If this model was going to be a final build I would have used construction adhesive on the joints and then used real wood veneer over the whole speaker.

It's only a full sized scale model held together by a few brad nails. I am going to disassemble it to use as a cuttng pattern for the real project. I built it to test my calculations and saw setup for accuracy. They were, so the next step is getting material for the real build. I plan on using maple or cherry, not MDF. I would weld a steel box together before I used MDF again.

[quote author=Steve Deckert link=1154300940/30#41 date=1154473484]I just looked at the prints and I'll be damn, the width measurement is gone! It is 12.5 inches btw. I'll update the print soon.

Steve [/quote]

Rear panel width 4.3 + 4.3 + 3.75 = 12.35 < 12.5. ??? "B" braces could have a slight gap with wider panel. Not that I think it really matters. I used 12.35 in width on my template and the "B" braces were flush at the back and along the sides. YMMV. I am considering applying a cloth cover (grill) between PL2 and PL3 panels so I would want the "B" brace slightly indented anyway to fit a cloth grill flush on the outside. I have not decided how to do this mod yet so I am kind of stuck at this point. I also am wary of any obstruction the cloth grill could have to air flow.